1. Field of the Invention
The present invention relates generally to packaging of semiconductor devices and, more particularly, to single die and multi-die semiconductor device packages as well as to methods of fabricating such packages and subcomponents thereof. The present invention is also directed to methods of fabricating probe cards and resulting structures.
2. Discussion of Related Art
Semiconductor dice are becoming ever-smaller in dimension, both from advances in fabrication technology and as so-called “shrinks” of initial semiconductor die designs are developed to increase the number of dice which may be fabricated on a wafer or other bulk semiconductor substrate. As a consequence, it becomes more difficult to employ lead frame-based packaging techniques using, for example, wire bonds to connect bond pads of a die to lead fingers of a lead frame due to diminishing size of bond pads as well as decreasing pitch (spacing) between adjacent bond pads, rendering it difficult, if not impossible in some circumstances, to place inner ends of lead fingers of a lead frame in close proximity to bond pads to which they are to be wire bonded.
Further, when bond pads are arranged along a central axis of a semiconductor die, such as is conventional in so-called “leads over chip,” or “LOC” packages, one may be faced with a choice between elongating and overcrowding lead fingers to place them in close proximity to the bond pads, or forming overly long wire bonds between the bond pads and remotely placed inner ends of lead fingers and risking potential breakage of the wire bonds or shorting between adjacent wire bonds when the package is being transfer-molded in an encapsulant by so-called “wire bond sweep” initiated by the flow front of the molten encapsulant moving over the active surface of the semiconductor die.
In addition, most conventional, lead frame-based packages do not facilitate high device density in conjunction with high multi-die device yields in terms of utilizing available “real estate” on a printed circuit board or other higher-level packaging.
Therefore, it would be desirable to provide a semiconductor device assembly packaging configuration which would accommodate ever-smaller semiconductor dice and their smaller, more closely pitched bond pads, and which would also facilitate the fabrication of highly reliable multi-die assemblies offering relatively high device densities.
It has also been recognized by those of ordinary skill in the art that it is desirable to probe test multiple semiconductor dice simultaneously, and that some dice employ bond pad configurations which render it difficult to fabricate probe cards suitable for probe testing a plurality of such dice without using a substrate including multiple layers of conductive traces. Further, in order to accommodate some bond pad configurations, it may be necessary to provide fairly long conductive paths from the location of a given interior contact to the periphery of the probe card substrate, inducing excessive capacitance, particularly if the paths comprise thin-film, planar metal traces.
Therefore, it would also be desirable to fabricate a relatively simple, yet robust, probe card using a single layer substrate which may be configured to accommodate any bond pad configuration resident on a plurality of dice to be probe tested simultaneously and minimize capacitance along the conductive paths leading from the contacts.